High-modulus glass fiber composition, glass fiber and composite material therefrom

ABSTRACT

The present invention provides a high-modulus glass fiber composition, a glass fiber and a composite material therefrom. The glass fiber composition comprises the following components expressed as percentage by weight: 55-64% SiO 2 , 13-24% Al 2 O 3 , 0.1-6% Y 2 O 3 , 3.4-10.9% CaO, 8-14% MgO, lower than 22% CaO+MgO+SrO, lower than 2% Li 2 O+Na 2 O+K 2 O, lower than 2% TiO 2 , lower than 1.5% Fe 2 O 3 , 0-1.2% La 2 O 3 , wherein the range of the weight percentage ratio C1=(Li 2 O+Na 2 O+K 2 O)/(Y 2 O 3 +La 2 O 3 ) is greater than 0.26. Said composition can significantly increase the glass elastic modulus, effectively inhibit the crystallization tendency of glass, decrease the liquidus temperature, secure a desirable temperature range (ΔT) for fiber formation and enhance the fining of molten glass, thus making it particularly suitable for production of high-modulus glass fiber with refractory-lined furnaces.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/738,563, filed Dec. 20, 2017, which is a National Entry ofInternational Application No. PCT/CN2016/075780, filed Mar. 7, 2016,which claims priority to Chinese Patent Application No. 201610113362.0,filed Feb. 29, 2016 and titled “High-Modulus Glass Fiber Composition,Glass Fiber and Composite Material Therefrom,” the contents of all ofwhich are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a high-modulus glass fiber composition,specifically to a glass fiber composition that can be used as areinforcing base material for composites, and to a glass fiber andcomposite material therefrom.

BACKGROUND FOR THE INVENTION

Glass fiber is an inorganic fiber material that can be used to reinforceresins to produce composite materials with good performance. As areinforcing base material for advanced composite materials, high-modulusglass fibers were originally used mainly in the aerospace industry orthe national defense industry. With the progress of science andtechnology and the development of economy, high-modulus glass fibershave been widely used in civil and industrial fields such as windblades, pressure vessels, offshore oil pipes and auto industry.

The original high-modulus glass compositions were based on anMgO—Al₂O₃—SiO₂ system and a typical solution was S-2 glass of Americancompany OC. The modulus of S-2 glass is 89-90 GPa; however, theproduction of this glass is excessively difficult, as its formingtemperature is up to about 1571° C. and its liquidus temperature up to1470° C. and therefore it is difficult to realize large-scale industrialproduction. Thus, OC stopped production of S-2 glass fiber andtransferred its patent to American company AGY.

Thereafter, OC developed HiPer-tex glass having a modulus of 87-89 GP,which were a trade-off for production scale by sacrificing some of theglass properties. However, as the design solution of HiPer-tex glass wasjust a simple improvement over that of S-2 glass, the formingtemperature and liquidus temperature remained high, which causesdifficulty in attenuating glass fiber and consequently in realizinglarge-scale industrial production. Therefore, OC also stopped productionof HiPer-tex glass fiber and transferred its patent to the Europeancompany 3B.

French company Saint-Gobain developed R glass that is based on anMgO—CaO—Al₂O₃—SiO₂ system, and its modulus is 86-89 GPa; however, thetotal contents of SiO₂ and Al₂O₃ remain high in the traditional R glass,and there is no effective solution to improve the crystallizationperformance, as the ratio of Ca to Mg is inappropriately designed, thuscausing difficulty in fiber formation as well as a great risk ofcrystallization, high surface tension and fining difficulty of moltenglass. The forming temperature of the R glass reaches 1410° C. and itsliquidus temperature up to 1350° C. All these have caused difficulty ineffectively attenuating glass fiber and consequently in realizinglarge-scale industrial production.

In China, Nanjing Fiberglass Research & Design Institute developed anHS2 glass having a modulus of 84-87 GPa. It primarily contains SiO₂,Al₂O₃ and MgO while also including certain contents of Li₂O, B₂O₃, CeO₂and Fe₂O₃. Its forming temperature is only 1245° C. and its liquidustemperature is 1320° C. Both temperatures are much lower than those of Sglass. However, since its forming temperature is lower than its liquidustemperature, which is unfavorable for the control of glass fiberattenuation, the forming temperature has to be increased andspecially-shaped tips have to be used to prevent a glass crystallizationphenomenon from occurring in the fiber attenuation process. This causesdifficulty in temperature control and also makes it difficult to realizelarge-scale industrial production.

To sum up, we find that, at present stage, the actual production ofvarious high-modulus glass fibers generally faces the difficulty oflarge-scale production with refractory-lined furnaces, specificallymanifested by comparably high liquidus temperature, high rate ofcrystallization, high forming temperature, high surface tension, finingdifficulty of molten glass and a narrow temperature range (ΔT) for fiberformation and even a negative ΔT. Therefore, most companies tend toreduce the production difficulty by compromising some of the glassproperties, thus making it impossible to improve the modulus of theabove-mentioned glass fibers with the growth of production scale. Theproblem of an insufficient modulus has long remained unresolved in theproduction of S glass fiber.

SUMMARY OF THE INVENTION

The present invention aims to solve the issue described above. Thepurpose of the present invention is to provide a high-modulus glassfiber composition which not only significantly improves the elasticmodulus of glass fiber, but also overcomes the technical problems in themanufacture of traditional high-modulus glasses including comparablyhigh liquidus temperature, high crystallization rate, high formingtemperature, high surface tension and fining difficulty of molten glass.The said glass fiber composition can significantly reduce the liquidustemperature and forming temperature of high-modulus glasses, help tolower the crystallization rate and bubbling ratio of the glass under thesame conditions and achieve a desirable ΔT value. Therefore, the glassfiber composition according to the present invention is particularlysuitable for large-scale production of high-modulus glass fibers withrefractory-lined furnaces.

According to one aspect of the present invention, a high-modulus glassfiber composition is provided comprising the following componentsexpressed as percentage by weight:

SiO₂ 55-64% Al₂O₃ 13-24% Y₂O₃ 0.1-6%   CaO  3.4-10.9% MgO  8-14% CaO +MgO + SrO <22%  Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃  0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.26.

wherein, the restricted weight percentage ratio C2=MgO/(CaO+SrO) is0.8-2.1;

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂  56-60.4% Al₂O₃ 13-24%  Y₂O₃ 0.1-6%   CaO 3.4-10.9% MgO 8-14% CaO +MgO + SrO <22%  SrO <3% Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%  La₂O₃  0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ isgreater than 0.26.

wherein, the restricted content range of Li₂O is 0.1-1.5% by weight;

wherein, the restricted content range of SrO is 0.1-2.5% by weight;

wherein, the restricted content range of CaO is 6-10.3% by weight;

wherein, the restricted content range of MgO is 8.6-13% by weight;

wherein, the restricted content range of Y₂O₃ is 0.5-5% by weight;

wherein, the restricted content range of Y₂O₃ is 1.5-5% by weight;

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂  56-60.4% Al₂O₃ 13-24%  Y₂O₃ 0.5-5%   CaO 3.4-10.9% MgO 8-14% CaO +MgO + SrO <22%  SrO <3% Li₂O 0.1-1.5%  Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃  0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ isgreater than 0.26, and the weight percentage ratio C2=MgO/(CaO+SrO) is0.8-2.1.

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂  56-60.4% Al₂O₃ 13-24%  Y₂O₃ 0.5-5%   CaO 3.4-10.9% MgO 8-14% CaO +MgO + SrO <22%  SrO <3% Li₂O 0.1-1.5%  Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃  0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.28, and the weight percentage ratio C2=MgO/(CaO+SrO)is 0.8-2.1.

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂   57-60.4% Al₂O₃   14-24% Y₂O₃ 0.5-5% CaO   5-10.6% MgO   8-14%CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1% Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.28, and the weight percentage ratio C2=MgO/(CaO+SrO)is 0.8-2.1.

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂   57-60.4% Al₂O₃ 14-23% Y₂O₃ 1.5-5%   CaO   6-10.3% MgO 8.6-13% CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.29, and the weight percentage ratio C2=MgO/(CaO+SrO)is 0.9-1.8.

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂   57-60.4% Al₂O₃   14-23% Y₂O₃ 1.5-5% CaO   6-10.3% MgO  8.6-13%CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1% Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.29, and the weight percentage ratio C2=MgO/(CaO+SrO)is 0.9-1.7.

wherein, the restricted content range of SrO is 0.1-2% by weight;

wherein, the restricted content range of La₂O₃ is 0.1-1% by weight;

wherein, the restricted content range of Y₂O₃ is 2-4% by weight;

wherein, the restricted content range of CaO is 6.5-10% by weight;

wherein, the restricted content range of MgO is greater than 12% but notgreater than 13% by weight;

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂ 55-64% Al₂O₃ 13-24% Y₂O₃ 0.1-6%   CaO  3.4-10.9% MgO greater than12% but not greater than 13% CaO + MgO + SrO <22%  Li₂O + Na₂O + K₂O <2%TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.26.

Wherein, the said composition comprises the following componentsexpressed as percentage by weight:

SiO₂ 55-64% Al₂O₃ greater than 19% but not greater than 21% Y₂O₃0.1-6%   CaO  3.4-10.9% MgO   8-10.5% CaO + MgO + SrO <22%  Li₂O +Na₂O + K₂O ≤1%  TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.26.

Wherein, the said composition can also include CeO₂ with a content rangeof 0-1% in percentage by weight.

According to another aspect of this invention, a glass fiber producedwith said glass fiber composition is provided.

Wherein, the elastic modulus of said glass fiber is 90-103 GPa.

According to yet another aspect of this invention, a composite materialincorporating said glass fiber is provided.

The main inventive points of the glass fiber composition according tothis invention include: introducing the rare earth oxide Y₂O₃, utilizingthe special compensation effect of yttrium in the glass structure,controlling the ratios of (Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) and MgO/(CaO+SrO)respectively, reasonably configuring the content ranges of Y₂O₃, La₂O₃,Li₂O, SrO, CaO, MgO and CaO+MgO+SrO, utilizing the synergistic effect ofyttrium and alkali metal oxides as well as the mixed alkali earth effectamong SrO, CaO and MgO, and a selective introduction of CeO₂ at anappropriate amount.

Specifically, the high-modulus glass fiber composition according to thepresent invention comprises the following components expressed aspercentage by weight:

SiO₂ 55-64% Al₂O₃ 13-24% Y₂O₃ 0.1-6%   CaO  3.4-10.9% MgO  8-14% CaO +MgO + SrO <22%  Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃  0-1.2%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃)is greater than 0.26.

The effect and content of each component in said glass fiber compositionis described as follows:

SiO₂ is a main oxide forming the glass network and has the effect ofstabilizing all the components. In the glass fiber composition of thepresent invention, the restricted content range of SiO₂ is 55-64%. Onthe basis of maintaining high mechanical properties and not addingdifficulties of fining the molten glass, the present inventionspecifically keeps the content of silica under a certain level.Preferably, the SiO₂ content range can be 56-60.4%, more preferably57-60.4%.

Al₂O₃ is another main oxide forming the glass network. When combinedwith SiO₂, it can have a substantive effect on the mechanical propertiesof the glass and a significant effect on preventing glass phaseseparation and on water resistance. The restricted content range ofAl₂O₃ in this invention is 13-24%. Too low of an Al₂O₃ content will makeit impossible to obtain sufficiently high mechanical properties,especially modulus; too high of a content will significantly increasethe risks of glass phase separation. Preferably, the Al₂O₃ content canbe 14-24%, more preferably 14-23%. In addition, the inventors haveunexpectedly found in an embodiment that, when the weight percentage ofAl₂O₃ is controlled to be greater than 19% and not greater than 21%, theweight percentage of MgO not greater than 10.5% and the total weightpercentage of Li₂O+Na₂O+K₂O not greater than 1%, the glass can haveexcellent mechanical properties and crystallization resistance as wellas a broad temperature range (ΔT) for fiber formation.

Both K₂O and Na₂O can reduce glass viscosity and are good fluxingagents. The inventors have found that, replacing Na₂O with K₂O whilekeeping the total amount of alkali metal oxides unchanged can reduce thecrystallization tendency of glass and improve the fiber formingperformance. Compared with Na₂O and K₂O, Li₂O can not only significantlyreduce glass viscosity thereby improving the glass melting performance,but also help greatly improve the mechanical properties of glass. Inaddition, a small amount of Li₂O provides considerable free oxygen,which helps more aluminum ions to form tetrahedral coordination,enhances the network structure of the glass and further improves themechanical properties of glass. However, as too many alkali metal ionsin the glass composition would affect the stability of the glass, theintroduced amount should be limited. Therefore, in the glass fibercomposition of the present invention, the restricted content range ofLi₂O+Na₂O+K₂O is lower than 2%. Furthermore, the restricted contentrange of Li₂O is 0.1-1.5%, and preferably 0.1-1%.

Y₂O₃ is an important rare earth oxide. The inventors find that Y₂O₃ isparticularly effective in increasing the glass modulus and inhibitingthe glass crystallization. As it is hard for Y³⁺ to enter the glassnetwork, it usually exists as external ions at the gaps of the glassnetwork. Y³⁺ ions have large coordination numbers, high field strengthand electric charge, and high accumulation capability. Due to thesefeatures, Y³⁺ ions can help not only to improve the structural stabilityof the glass and increase the glass modulus, but also effectivelyprevent the movement and arrangement of other ions so as to minimize thecrystallization tendency of the glass. In the glass fiber composition ofthis invention, the restricted content range of Y₂O₃ is 0.1-6%.Preferably, the Y₂O₃ content can be 0.5-5%, more preferably 1.5-5%, andstill more preferably 2-4%.

La₂O₃ is also an important rare earth oxide. The inventors have foundthat, when used alone, La₂O₃ shows a weaker effect in increasing themodulus and inhibiting the crystallization but offers a better finingeffect, as compared with Y₂O₃. In the meantime, as the molar mass andionic radiuses of lanthanum are both big, an excessive introduced amountwould not only weaken its effect in increasing the glass properties, butalso even undermine the stability of the glass structure and increasethe glass density. Therefore, the introduced amount of La₂O₃ should belimited. In the glass fiber composition of this invention, La₂O₃ can beoptionally introduced with a small amount. The restricted content ofLa₂O₃ can be 0-1.2%, and further can be 0.1-1%.

The inventors also find that the coordination state of Y₂O₃ is closelyrelated to the content of free oxygen in the glass. Y₂O₃ in crystallinestate has vacancy defects and, when Y₂O₃ are introduced to the glass,these vacancy defects would be filled by other oxides, especially alkalimetal oxides. Different filling degrees would lead to differentcoordination state and stacking density of Y₂O₃, thus having asignificant effect on the glass properties. Similarly, La₂O₃ also needsa certain amount of oxygen to fill the vacancies. In order to acquiresufficient free oxygen and accordingly achieve a more compact stackingstructure and better crystallization resistance, the restricted range ofthe weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) in thepresent invention is greater than 0.26, preferably greater than 0.28,and more preferably greater than 0.29.

CaO, MgO and SrO primarily have the effect of controlling the glasscrystallization and regulating the glass viscosity and the rate ofhardening of molten glass. Particularly on the control of the glasscrystallization, the inventors have obtained unexpected effects bycontrolling the introduced amounts of them and the ratios between them.Generally, for a high-performance glass based on the MgO—CaO—Al₂O₃—SiO₂system, the crystal phases it contains after glass crystallizationinclude mainly diopside (CaMgSi₂O₆) and anorthite (CaAl₂Si₂O₃). In orderto effectively inhibit the tendency for two crystal phases tocrystallize and decrease the glass liquidus temperature and the rate ofcrystallization, this invention has rationally controlled the totalcontent of CaO+MgO+SrO and the weight percentage ratio C2=MgO/(CaO+SrO)and utilized the mixed alkali earth effect to form a compact stackingstructure, so that more energy are needed for the crystal nucleases toform and grow. In addition, as the radius of Sr²⁺ ions is big, not onlythe ion itself is difficult to move but also it can retard the movementand restructuring of Mg²⁺ and Ca²⁺ ions under the same conditions, thusachieving the target of inhibiting the crystallization tendency of theglass while optimizing the rate of hardening of molten glass. In theglass fiber composition of this invention, the restricted range of thetotal content of CaO+MgO+SrO is less than 22%, and preferably less than21%. Still, in one embodiment of this invention, the restricted range ofthe weight percentage ratio C2=MgO/(CaO+SrO) can be 0.8-2.1, preferably0.9-1.8, and more preferably 0.9-1.7; in another embodiment of thisinvention, when the content of MgO is above 12%, there will be no suchrestrictions as described above for the range of C2.

In the glass fiber composition of the present invention, the restrictedcontent range of CaO can be 3.4-10.9%, preferably 5-10.6%, morepreferably can be 6-10.3%, and still more preferably 6.5-10%; therestricted content range of MgO can be 8-14%, preferably 8.6-13%, andmore preferably greater than 12% but not greater than 13%; therestricted content range of SrO can be lower than 3%, preferably0.1-2.5%, and more preferably 0.1-2%.

TiO₂ can not only reduce the glass viscosity at high temperature, butalso has a certain fluxing effect. However, since titanium ions have acertain coloring effect and such coloring effect becomes particularlysignificant when the TiO₂ content exceeds 2%, which will affect theappearance of glass fiber reinforced articles to some extent. Therefore,in the glass fiber composition of the present invention, the restrictedcontent range of TiO₂ is lower than 2%.

Fe₂O₃ facilitates the melting of glass and can also improve thecrystallization performance of glass. However, since ferric ions andferrous ions have a coloring effect, the introduced amount should belimited. Therefore, in the glass fiber composition of the presentinvention, the restricted content range of Fe₂O₃ is lower than 1.5%.

In the glass fiber composition of the present invention, a selectiveintroduction of CeO₂ at an appropriate amount can further improve thecrystallization tendency and fining of the glass, and the restrictedcontent range of CeO₂ can be 0-1%.

In addition, the glass fiber composition of the present invention caninclude small amounts of other components with a total content notgreater than 2%.

In the glass fiber composition of the present invention, the beneficialeffects produced by the aforementioned selected ranges of the componentswill be explained by way of examples through the specific experimentaldata.

The following are embodiments of preferred content ranges of thecomponents contained in the glass fiber composition according to thepresent invention.

Preferred Embodiment 1

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂  56-60.4% Al₂O₃ 13-24%  Y₂O₃ 0.5-5%   CaO 3.4-10.9% MgO 8-14% CaO +MgO + SrO <22%  SrO <3% Li₂O 0.1-1.5%  Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃  0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.

Preferred Embodiment 2

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂   56-60.4% Al₂O₃ 13-24% Y₂O₃ 0.5-5%   CaO  3.4-10.9% MgO  8-14%CaO + MgO + SrO <22%  SrO <3% Li₂O 0.1-1.5% Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.

Preferred Embodiment 3

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

DS SiO₂ 57-60.4% Al₂O₃ 14-24%   Y₂O₃ 0.5-5%   CaO  5-10.6% MgO 8-14% CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃ 0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.

Preferred Embodiment 4

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

S SiO₂ 57-60.4% Al₂O₃ 14-23%   Y₂O₃ 1.5-5%   CaO  6-10.3% MgO 8.6-13% CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃ 0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.29, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.9-1.8.

Preferred Embodiment 5

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SSA SiO₂ 57-60.4% Al₂O₃ 14-23%   Y₂O₃ 1.5-5%   CaO  6-10.3% MgO 8.6-13% CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃ 0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.29, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.9-1.7.

According to the preferred embodiment 5, the liquidus temperature of theglass composition is not greater than 1320° C., preferably not greaterthan 1300° C., and more preferably not greater than 1250° C., and theelastic modulus of the glass fiber made thereof is 90-103 Gpa.

Preferred Embodiment 6

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂   57-60.4% Al₂O₃   14-23% Y₂O₃ 1.5-5% CaO   6-10.3% MgO  8.6-13%CaO + MgO + SrO <21%  SrO 0.1-2% Li₂O 0.1-1% Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.29, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.9-1.7.

Preferred Embodiment 7

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂   57-60.4% Al₂O₃   14-24% Y₂O₃ 0.5-5% CaO   5-10.6% MgO   8-14%CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1% Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃ 0.1-1%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.

Preferred Embodiment 8

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂   57-60.4% Al₂O₃ 14-24% Y₂O₃ 2-4% CaO   5-10.6% MgO  8-14% CaO +MgO + SrO <21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.

Preferred Embodiment 9

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂ 57-60.4% Al₂O₃ 14-24%   Y₂O₃ 0.5-5%   CaO 6.5-10%  MgO 8-14%  CaO +MgO + SrO <21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂ <2%Fe₂O₃ <1.5%   La₂O₃ 0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.

Preferred Embodiment 10

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂ 55-64% Al₂O₃ 13-24% Y₂O₃ 0.1-6%   CaO  3.4-10.9% MgO greater than12% and not greater than 13% CaO + MgO + SrO <22%  Li₂O + Na₂O + K₂O <2%TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26.

According to the preferred embodiment 10, the elastic modulus of theglass fiber made thereof is greater than 95 Gpa.

Preferred Embodiment 11

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂ 55-64% Al₂O₃ greater than 19% and not greater than 21% Y₂O₃0.1-6%   CaO  3.4-10.9% MgO   8-10.5% CaO + MgO + SrO <22%  Li₂O +Na₂O + K₂O ≤1% TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃   0-1.2%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26.

Preferred Embodiment 12

The high-modulus glass fiber composition according to the presentinvention comprises the following components expressed as percentage byweight:

SiO₂   57-60.4% Al₂O₃ 14-24% Y₂O₃ 0.5-5%   CaO   5-10.6% MgO  8-14%CaO + MgO + SrO <21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃   0-1.2% CeO₂ 0-1%

In addition, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the range ofthe weight percentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.

DETAILED DESCRIPTION OF THE INVENTION

In order to better clarify the purposes, technical solutions andadvantages of the examples of the present invention, the technicalsolutions in the examples of the present invention are clearly andcompletely described below. Obviously, the examples described herein arejust part of the examples of the present invention and are not all theexamples. All other exemplary embodiments obtained by one skilled in theart on the basis of the examples in the present invention withoutperforming creative work shall all fall into the scope of protection ofthe present invention. What needs to be made clear is that, as long asthere is no conflict, the examples and the features of examples in thepresent application can be arbitrarily combined with each other.

The basic concept of the present invention is that the components of theglass fiber composition expressed as percentage by weight are: 55-64%SiO₂, 13-24% Al₂O₃, 0.1-6% Y₂O₃, 3.4-10.9% CaO, 8-14% MgO, lower than22% CaO+MgO+SrO, lower than 2% Li₂O+Na₂O+K₂O, lower than 2% TiO₂, lowerthan 1.5% Fe₂O₃, 0-1.2% La₂O₃, wherein the range of the weightpercentage ratio C1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26.Said composition can significantly increase the glass elastic modulus,effectively inhibit the crystallization tendency of glass, decrease theliquidus temperature, secure a desirable temperature range (ΔT) forfiber formation and enhance the fining of molten glass, thus making itparticularly suitable for high modulus glass fiber production withrefractory-lined furnaces.

The specific content values of SiO₂, Al₂O₃, Y₂O₃, CaO, MgO, Li₂O, Na₂O,K₂O, Fe₂O₃, TiO₂, SrO and La₂O₃ in the glass fiber composition of thepresent invention are selected to be used in the examples, andcomparisons with S glass, traditional R glass and improved R glass aremade in terms of the following six property parameters,

(1) Forming temperature, the temperature at which the glass melt has aviscosity of 10³ poise.

(2) Liquidus temperature, the temperature at which the crystal nucleusesbegin to form when the glass melt cools off—i.e., the upper limittemperature for glass crystallization.

(3) ΔT value, which is the difference between the forming temperatureand the liquidus temperature and indicates the temperature range atwhich fiber drawing can be performed.

(4) Peak crystallization temperature, the temperature which correspondsto the strongest peak of glass crystallization during the DTA testing.Generally, the higher this temperature is, the more energy is needed bycrystal nucleuses to grow and the lower the glass crystallizationtendency is.

(5) Elastic modulus, the linear elastic modulus defining the ability ofglass to resist elastic deformation, which is to be measured as perASTM2343.

(6) Amount of bubbles, to be determined in a procedure set out asfollows: Use specific moulds to compress the glass batch materials ineach example into samples of same dimension, which will then be placedon the sample platform of a high temperature microscope. Heat thesamples according to standard procedures up to the pre-set spatialtemperature 1500° C. and then directly cool them off with the coolinghearth of the microscope to the ambient temperature without heatpreservation. Finally, each of the glass samples is examined under apolarizing microscope to determine the amount of bubbles in the samples.A bubble is identified according to a specific amplification of themicroscope.

The aforementioned six parameters and the methods of measuring them arewell-known to one skilled in the art. Therefore, these parameters can beeffectively used to explain the properties of the glass fibercomposition of the present invention.

The specific procedures for the experiments are as follows: Eachcomponent can be acquired from the appropriate raw materials. Mix theraw materials in the appropriate proportions so that each componentreaches the final expected weight percentage. The mixed batch melts andthe molten glass refines. Then the molten glass is drawn out through thetips of the bushings, thereby forming the glass fiber. The glass fiberis attenuated onto the rotary collet of a winder to form cakes orpackages. Of course, conventional methods can be used to deep processthese glass fibers to meet the expected requirements.

The exemplary embodiments of the glass fiber composition according tothe present invention are given below.

EXAMPLE 1

SiO₂ 59.5% Al₂O₃ 16.7% CaO  8.9% MgO  9.5% Y₂O₃  1.8% Na₂O 0.23% K₂O0.36% Li₂O 0.75% Fe₂O₃ 0.44% TiO₂ 0.43% SrO  1.0%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ is0.74, and the weight percentage ratio C2=MgO/(CaO+SrO) is 0.96.

In Example 1, the measured values of the six parameters arerespectively:

Forming temperature 1298° C. Liquidus temperature 1205° C. ΔT 93° C.Peak crystallization temperature 1023° C. Elastic modulus 93.9 GPaAmount of bubbles 11

EXAMPLE 2

SiO₂ 59.3% Al₂O₃ 17.0% CaO  8.2% MgO  9.7% Y₂O₃  3.3% Na₂O 0.22% K₂O0.37% Li₂O 0.75% Fe₂O₃ 0.44% TiO₂ 0.44%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ is0.41, and the weight percentage ratio C2=MgO/(CaO+SrO) is 1.18.

In Example 2, the measured values of the six parameters arerespectively:

Forming temperature 1300° C. Liquidus temperature 1206° C. ΔT 94° C.Peak crystallization temperature 1024° C. Elastic modulus 95.6 GPaAmount of bubbles 8

EXAMPLE 3

SiO₂ 58.2% Al₂O₃ 19.2% CaO  6.7% MgO   10% Y₂O₃  3.4% Na₂O 0.19% K₂O0.23% Li₂O 0.55% Fe₂O₃ 0.44% TiO₂ 0.82%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ is0.29, and the weight percentage ratio C2=MgO/(CaO+SrO) is 1.49.

In Example 3, the measured values of the six parameters arerespectively:

Forming temperature 1305° C. Liquidus temperature 1200° C. ΔT 105° C.Peak crystallization temperature 1024° C. Elastic modulus 97.0 GPaAmount of bubbles 11

EXAMPLE 4

SiO₂ 58.8% Al₂O₃ 17.4% CaO  5.8% MgO 10.4% Y₂O₃  5.0% Na₂O 0.29% K₂O0.49% Li₂O 0.75% Fe₂O₃ 0.43% TiO₂ 0.40%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ is0.31, and the weight percentage ratio C2=MgO/(CaO+SrO) is 1.79.

In Example 4, the measured values of the six parameters arerespectively:

Forming temperature 1303° C. Liquidus temperature 1213° C. ΔT 90° C.Peak crystallization temperature 1029° C. Elastic modulus 100.3 GPaAmount of bubbles 9

EXAMPLE 5

SiO₂ 59.3% Al₂O₃ 17.1% CaO  7.6% MgO 10.4% Y₂O₃  3.1% Na₂O 0.21% K₂O0.34% Li₂O 0.45% Fe₂O₃ 0.44% TiO₂ 0.43% SrO  0.3%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ is0.32, and the weight percentage ratio C2=MgO/(CaO+SrO) is 1.37.

In Example 5, the measured values of the six parameters arerespectively:

Forming temperature 1296° C. Liquidus temperature 1206° C. ΔT 90° C.Peak crystallization temperature 1021° C. Elastic modulus 94.1 GPaAmount of bubbles 10

EXAMPLE 6

SiO₂ 59.3% Al₂O₃ 16.3% CaO  6.1% MgO 12.2% Y₂O₃  3.4% Na₂O 0.23% K₂O0.46% Li₂O 0.50% Fe₂O₃ 0.44% TiO₂ 0.82%

In addition, the weight percentage ratio C1=(Li₂O+Na₂O+K₂O)/Y₂O₃ is0.35, and the weight percentage ratio C2=MgO/(CaO+SrO) is 2.

In Example 6, the measured values of the six parameters arerespectively:

Forming temperature 1300° C. Liquidus temperature 1220° C. ΔT 80° C.Peak crystallization temperature 1020° C. Elastic modulus 97.1 GPaAmount of bubbles 10

Comparisons of the property parameters of the aforementioned examplesand other examples of the glass fiber composition of the presentinvention with those of traditional E glass, traditional R glass andimproved R glass are further made below by way of tables, wherein thecomponent contents of the glass fiber composition are expressed asweight percentage. What needs to be made clear is that the total amountof the components in the examples is slightly less than 100%, and itshould be understood that the remaining amount is trace impurities or asmall amount of components which cannot be analyzed.

TABLE 1A A1 A2 A3 A4 A5 A6 A7 Component SiO₂ 59.4 59.3 59.5 59.4 60.158.2 59.3 Al₂O₃ 16.9 17.1 16.6 16.7 17.0 19.2 16.3 CaO 7.8 7.6 7.3 9.710.2 6.7 6.1 MgO 9.6 10.4 10.0 9.4 9.8 10.0 12.2 Y₂O₃ 3.1 3.1 3.1 2.40.5 3.4 3.4 Na₂O 0.21 0.21 0.21 0.23 0.21 0.19 0.23 K₂O 0.42 0.34 0.510.38 0.41 0.23 0.46 Li₂O 0.71 0.45 0.60 0.70 0.65 0.55 0.50 Fe₂O₃ 0.440.44 0.44 0.44 0.44 0.44 0.44 TiO₂ 0.43 0.43 0.37 0.42 0.44 0.82 0.82SrO 0.7 0.3 1.1 — — — — Ratio C1 0.43 0.32 0.43 0.55 2.54 0.29 0.35 C21.13 1.37 1.19 0.97 0.96 1.49 2 Parameter Forming 1294 1296 1295 12981300 1305 1300 temperature/° C. Liquidus 1202 1206 1199 1200 1208 12001220 temperature/° C. ΔT/° C. 92 90 96 98 92 105 80 Peak 1023 1021 10251022 1018 1024 1020 crystallization temperature/° C. Elastic 95.0 94.195.8 93.3 90.9 97.0 97.1 modulus/GPa Amount of 9 10 11 10 12 11 10bubbles/pcs

TABLE 1B A8 A9 A10 A11 A12 A13 A14 Component SiO₂ 59.1 59.1 59.3 59.459.1 60.4 61.0 Al₂O₃ 16.9 17.0 16.8 16.7 16.8 16.7 16.2 CaO 6.8 6.9 10.09.0 9.9 9.2 8.5 MgO 10.8 10.8 9.8 9.4 9.3 9.7 9.7 Y₂O₃ 3.7 3.7 2.0 3.03.0 0.5 0.9 Na₂O 0.21 0.23 0.21 0.32 0.21 0.21 0.21 K₂O 0.42 0.36 0.320.58 0.39 0.43 0.43 Li₂O 0.61 0.41 0.37 0.45 0.20 0.75 0.75 Fe₂O₃ 0.440.44 0.44 0.44 0.44 0.44 0.44 TiO₂ 0.43 0.43 0.42 0.42 0.42 0.44 0.42SrO 0.3 0.3 — — — — — La₂O₃ — — — — — 1 1.2 Ratio C1 0.34 0.27 0.45 0.450.27 0.93 0.66 C2 1.52 1.50 0.98 1.04 0.94 1.05 1.14 Parameter Forming1295 1297 1292 1297 1296 1296 1302 temperature/° C. Liquidus 1206 12121204 1202 1206 1205 1203 temperature/° C. ΔT/° C. 89 85 88 95 90 91 100Peak 1028 1026 1020 1023 1021 1020 1023 crystallization temperature/° C.Elastic 97.1 95.7 92.9 94.3 93.5 91.2 92.1 modulus/GPa Amount of 8 9 109 10 6 5 bubbles/pcs

TABLE 1C Traditional Improved A15 A16 A17 A18 S glass R glass R glassComponent SiO₂ 58.8 59.7 59.5 59.3 65 60 60.75 Al₂O₃ 17.4 16.8 16.7 17.025 25 15.80 CaO 5.8 10.1 8.9 8.2 — 9 13.90 MgO 10.4 9.3 9.5 9.7 10 67.90 Y₂O₃ 5.0 1.6 1.8 3.3 — — — Na₂O 0.29 0.22 0.23 0.22 trace trace0.73 amount amount K₂O 0.49 0.38 0.36 0.37 trace trace amount amountLi₂O 0.75 0.75 0.75 0.75 — — 0.48 Fe₂O₃ 0.43 0.44 0.44 0.44 trace trace0.18 amount amount TiO₂ 0.40 0.43 0.43 0.44 trace trace 0.12 amountamount SrO — — 1.0 — — — — Ratio C1 0.31 0.84 0.74 0.41 — — — C2 1.790.92 0.96 1.18 — 0.67 0.57 Parameter Forming 1303 1299 1298 1300 1571 1430 1278 temperature/° C. Liquidus 1213 1210 1205 1206 1470  1350 1210temperature/° C. ΔT/° C. 90 89 93 94 101  80 68 Peak 1029 1021 1023 1024— 1010 1016 crystallization temperature/° C. Elastic 100.3 93.0 93.995.6 89 88 87 modulus/GPa Amount of 9 10 11 8 40 30 25 bubbles/pcs

It can be seen from the values in the above tables that, compared withthe S glass and traditional R glass, the glass fiber composition of thepresent invention has the following advantages: (1) much higher elasticmodulus; (2) much lower liquidus temperature, which helps to reducecrystallization risk and increase the fiber drawing efficiency;relatively high peak crystallization temperature, which indicates thatmore energy is needed for the formation and growth of crystal nucleusesduring the crystallization process of glass, i.e. the crystallizationrisk of the glass of the present invention is smaller under the sameconditions; (3) smaller amount of bubbles, which indicates a betterrefining of molten glass.

Both S glass and traditional R glass cannot enable the achievement oflarge-scale production with refractory-lined furnaces and, with respectto improved R glass, part of the glass properties is compromised toreduce the liquidus temperature and forming temperature, so that theproduction difficulty is decreased and the production withrefractory-lined furnaces could be achieved. By contrast, the glassfiber composition of the present invention not only has a sufficientlylow liquidus temperature and forming temperature which permit theproduction with refractory-lined furnaces, but also significantlyincreases the glass modulus, thereby resolving the technical bottleneckthat the modulus of S glass fiber and R glass fiber cannot be improvedwith the growth of production scale.

The glass fiber composition according to the present invention can beused for making glass fibers having the aforementioned excellentproperties.

The glass fiber composition according to the present invention incombination with one or more organic and/or inorganic materials can beused for preparing composite materials having excellent performances,such as glass fiber reinforced base materials.

Finally, what should be made clear is that, in this text, the terms“contain”, “comprise” or any other variants are intended to mean“nonexclusively include” so that any process, method, article orequipment that contains a series of factors shall include not only suchfactors, but also include other factors that are not explicitly listed,or also include intrinsic factors of such process, method, object orequipment. Without more limitations, factors defined by such phrase as“contain a . . . ” do not rule out that there are other same factors inthe process, method, article or equipment which include said factors.

The above examples are provided only for the purpose of illustratinginstead of limiting the technical solutions of the present invention.Although the present invention is described in details by way ofaforementioned examples, one skilled in the art shall understand thatmodifications can also be made to the technical solutions embodied byall the aforementioned examples or equivalent replacement can be made tosome of the technical features. However, such modifications orreplacements will not cause the resulting technical solutions tosubstantially deviate from the spirits and ranges of the technicalsolutions respectively embodied by the examples of the presentinvention.

INDUSTRIAL APPLICABILITY OF THE INVENTION

The glass fiber composition of the present invention not only has asufficiently low liquidus temperature and forming temperature whichenable the production with refractory-lined furnaces, but alsosignificantly increases the glass modulus, thereby resolving thetechnical bottleneck that the modulus of S glass fiber and R glass fibercannot be improved with the enhanced production scale. Compared with thecurrent main-stream high-modulus glasses, the glass fiber composition ofthe present invention has made a breakthrough in terms of elasticmodulus, crystallization performance and fining performance of theglass, with significantly improved modulus, remarkably reducedcrystallization risk and relatively small amount of bubbles under thesame conditions. Thus, the overall technical solution of the presentinvention enables an easy achievement of large-scale production withrefractory-lined furnaces.

What is claimed is:
 1. A high-modulus glass fiber composition,comprising the following components expressed as percentage by weight:SiO₂ 55-64% Al₂O₃ 16.7-24%   Y₂O₃ 0.1-2.4% CaO  3.4-10.9% MgO 9.4-14% CaO + MgO + SrO <22%  Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃  0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26.
 2. Thehigh-modulus glass fiber composition according to claim 1, wherein thecontent range of Li₂O by weight is 0.1-1.5%.
 3. The high-modulus glassfiber composition according to claim 1, wherein the content range of SrOby weight is 0.1-2.5%.
 4. The high-modulus glass fiber compositionaccording to claim 1, wherein the content range of CaO by weight is6-10.3%.
 5. The high-modulus glass fiber composition according to claim1, wherein the content range of MgO by weight is 9.4-13%.
 6. Thehigh-modulus glass fiber composition according to claim 1, wherein thecontent range of La₂O₃ by weight is 0.1-1%.
 7. The high-modulus glassfiber composition according to claim 1, comprising CeO₂ with the weightpercentage of 0-1%.
 8. The high-modulus glass fiber compositionaccording to claim 1, wherein the range of the weight percentage ratioC2=MgO/(CaO+SrO) is 0.8-2.1.
 9. The high-modulus glass fiber compositionaccording to claim 8, wherein the content range of Y₂O₃ by weight is0.5-2.4%.
 10. The high-modulus glass fiber composition according toclaim 8, wherein the content range of Y₂O₃ by weight is 1.5-2.4%.
 11. Aglass fiber, characterized by, being produced from the glass fibercompositions according to claim
 1. 12. The glass fiber according toclaim 11, characterized by, having the range of the elastic modulus90-103 GPa.
 13. A composite material, characterized by, incorporatingthe glass fiber according to claim
 11. 14. The high-modulus glass fibercomposition according to claim 1, comprising the following componentsexpressed as percentage by weight: SiO₂ 56-60.4% Al₂O₃ 16.7-24%   Y₂O₃0.1-2.4%   CaO 3.4-10.9%  MgO 9.4-14%  CaO + MgO + SrO <22%  SrO <3%Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%   La₂O₃ 0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26.
 15. Thehigh-modulus glass fiber composition according to claim 1, comprisingthe following components expressed as percentage by weight: SiO₂56-60.4% Al₂O₃ 16.7-24%   Y₂O₃ 0.5-2.4%   CaO 3.4-10.9%  MgO 9.4-14% CaO + MgO + SrO <22%  SrO <3% Li₂O 0.1-1.5%   Li₂O + Na₂O + K₂O <2% TiO₂<2% Fe₂O₃ <1.5%   La₂O₃ 0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26, and the weightpercentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.
 16. The high-modulus glassfiber composition according to claim 1, comprising the followingcomponents expressed as percentage by weight: SiO₂ 56-60.4% Al₂O₃16.7-24%   Y₂O₃ 0.5-2.4%   CaO 3.4-10.9%  MgO 9.4-14%  CaO + MgO + SrO<22%  SrO <3% Li₂O 0.1-1.5%   Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃<1.5%   La₂O₃ 0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the weightpercentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.
 17. The high-modulus glassfiber composition according to claim 1, comprising the followingcomponents expressed as percentage by weight: SiO₂ 57-60.4% Al₂O₃16.7-24%   Y₂O₃ 0.5-2.4%   CaO  5-10.6% MgO 9.4-14%  CaO + MgO + SrO<21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%  La₂O₃ 0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.28, and the weightpercentage ratio C2=MgO/(CaO+SrO) is 0.8-2.1.
 18. The high-modulus glassfiber composition according to claim 1, comprising the followingcomponents expressed as percentage by weight: SiO₂ 57-60.4% Al₂O₃16.7-23%   Y₂O₃ 1.5-2.4%   CaO  6-10.3% MgO 9.4-13%  CaO + MgO + SrO<21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%  La₂O₃ 0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.29, and the weightpercentage ratio C2=MgO/(CaO+SrO) is 0.9-1.8.
 19. The high-modulus glassfiber composition according to claim 1, comprising the followingcomponents expressed as percentage by weight: SiO₂ 57-60.4% Al₂O₃16.7-23%   Y₂O₃ 1.5-2.4%   CaO  6-10.3% MgO 9.4-13%  CaO + MgO + SrO<21%  SrO <3% Li₂O 0.1-1%   Li₂O + Na₂O + K₂O <2% TiO₂ <2% Fe₂O₃ <1.5%  La₂O₃ 0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.29, and the weightpercentage ratio C2=MgO/(CaO+SrO) is 0.9-1.7.
 20. The high-modulus glassfiber composition according to claim 1, comprising the followingcomponents expressed as percentage by weight: SiO₂ 55-64% Al₂O₃ greaterthan 19% and not greater than 21% Y₂O₃ 0.1-2.4% CaO  3.4-10.9% MgO 9.4-10.5% CaO + MgO + SrO <22%  Li₂O + Na₂O + K₂O ≤1% TiO₂ <2% Fe₂O₃<1.5%   La₂O₃   0-1.2%

wherein, the range of the weight percentage ratioC1=(Li₂O+Na₂O+K₂O)/(Y₂O₃+La₂O₃) is greater than 0.26.